variable.attack_time Fails With Villager Runtime ID

When creating a mob that can use melee attacks and uses the runtime-id 'minecraft:villager_v2', the variable 'attack_time' becomes unknown and attack animations won't work correctly.

Steps To Reproduce:

1. Add ' "minecraft:runtime_id": "minecraft:villager_v2" ' to any custom hostile mob
2. Any previously working attack animations will no longer work
3. Several errors will begin appearing in the content log

Expected Behavior:

• The attack_time variable (along with other hidden variables) is universal and can be used by all mobs, regardless of runtime-id.

Actual Behavior:

• Adding the villager runtime id to a mob breaks the attack_time variable